This invention relates to a pollution control system that can be adapted to existing engines, particularly heavy duty engines used in transport and mass transit systems. Pollution from heavy duty engines has reached a critical proportion, since many of the engines have been in the past exempt from pollution control regulations. However, with the increasing concern over urban pollution, regulation will become increasingly stringent for all vehicles, including those vehicles which have enjoyed past exemptions. Of particular concern is the diesel engine which frequently emits carbon particulate matter that is being recognized as a serious health concern. While advanced diesel engines have been designed that substantially reduce the emission of pollutants, existing engines lack those controls that provide for efficient combustion. Furthermore, existing engines easily become out of tune resulting in substantial increase in emissions.
Problems in the design of existing diesel engines are traced to poor combustion chamber configurations, inadequate air-fuel mixtures, insufficient atomization of injected fuels, and the characteristic high carbon content of conventional fuels.
The use of superchargers has improved the ability to supply sufficient air for combustion under most conditions. However, because of the inefficiency of most supercharger designs, substantial extraction of power is required for minimal compression of air. Additionally, while it has been proposed to utilize fuels that are rich in hydrogen such as methanol, alcohol and liquefied natural gas, the existing fuel injection systems are inadequate to handle the lower Btu content of the preferred fuel. Since the Btu content is approximately 50% less then existing diesel fuels or gasoline, the fuel injection systems of the engines must be totally revised in order to accommodate the necessary larger volumes of fuel required for normal operation. Furthermore, the substantially increased volume of fuel that is injected during each engine cycle creates ignition problems due to the quantity of cold fuel required to be vaporized. The proposed combined fuel engine for pollution reduction solves these problems and improves engine performance at the same time that pollution is substantially reduced.